Labor's dominance comes to an end, but Conservatives may lack a majority. The Liberal Democrats, who could play the role of kingmaker, fall short of their buoyed expectations.

Reporting from London — Britain looked set for a period of political uncertainty as voters appeared to usher in a stalemated Parliament, with the opposition Conservatives on track to capture the most seats in a volatile national election Thursday but not enough to form a majority government.

UPDATE: 3:05 a.m. The British election has officially resulted in a "hung parliament" in which no party has an absolute majority in the House of Commons. The opposition Conservatives have won the most seats in Parliament, beating the ruling Labor Party, but have fallen short of a majority. Nick Clegg, leader of the third-place, potentially king-making Liberal Democrats, said Friday morning that the Conservatives should have first shot at forming a government "on its own or by reaching out to other parties."

Exit polls projected a harsh blow to the ruling Labor Party, whose dominance after 13 years of government has apparently come to an end. Voters denied the party of Prime Minister Gordon Brown an uncontestable and unprecedented fourth term, pushing it into second place.

That leaves the Liberal Democrats, a smaller third party, potentially holding the balance of power in the House of Commons, even though its projected haul of seats was disappointingly less than expected after its surge in popularity in recent weeks.

Such was the closeness of the vote, however, that six hours after the polls closed, the outcome remained too much in flux to call with certainty.

If the exit polls hold, the result would be Britain's first so-called hung Parliament in 36 years. What probably lies ahead is an intense period of backroom talks and horse-trading to see which party gets to form a government and which leader emerges as prime minister.

Many bets are on David Cameron, the 43-year-old leader of the Conservatives, serving at the head of a minority government as the youngest prime minister in nearly 200 years.

Without a legislative majority, however, Cameron would be forced to work with other parties issue by issue rather than steamroll his agenda of budget cuts and smaller government through Parliament. A coalition with the Liberal Democrats is possible, although the two parties have little in common.

"What is clear from these results is that the country, our country, wants change. That change is going to require new leadership," Cameron said early Friday, adding that he would "put the national interest first."

But Brown isn't out of the picture completely. Still open is the idea of an alliance between the Liberal Democrats and Labor, which Brown was reported to be pushing for early Friday.

Although the two parties are closer ideologically than either is with the Tories, Nick Clegg, the Liberal Democratic leader, is known to dislike the continued presence of Brown as prime minister.

The broody Scotsman, who became prime minister when Tony Blair stepped down in 2007, is deeply unpopular with many Britons, who blame him for a struggling economy barely out of recession. Many of his fellow Laborites will also now hold him responsible for a grim poll result that saw the party lose millions of votes to the Conservatives.

Addressing supporters in his parliamentary constituency in Scotland, Brown, 59, said: "My duty to this country coming out of this election is to play my part in Britain having a strong, stable and principled government, able to lead Britain into sustained economic recovery and able to implement our commitments to far-reaching reform of our political system, upon which there is a growing consensus in our country."

But Cameron scoffed at any continued role in government for Brown.

"I believe it is already clear that the Labor government has lost its mandate to govern our country," he said.

Cameron fought on a platform of having modernized the Tories, overhauling its reputation as the "nasty party" of anti-immigrant, anti-European sentiment into one that embraces gay rights, environmental protection and a commitment to help the poor.

As the campaign unfolded, voters were clearly galvanized by a message of change from both the Conservatives and the Liberal Democrats, convinced that the time had come to give fresh faces and ideas a try. The same attitude was widespread in 1997, when the Tories were ousted after 18 years in power, giving way to a new-look Labor Party under Blair's charismatic leadership.

"It's a fork in the road," Tony Travers, a political scientist at the London School of Economics, said of Thursday's poll. "With a tired-looking government, there was always a real chance there'd be a change.... They want to throw the present lot out."

That was on Rosemary Smith's mind as she cast her vote in northern London.

"We need a Conservative government now," said Smith, 74, a retired development worker.

For many voters, the No. 1 issue was the British economy, the last of the world's biggest economies to emerge from recession, and only haltingly at that.